Stepless change speed transmission with adjustable throw crank mechanism



Jan. 23, 1968 SHIGEO ISHIOKA 3,364,759

STEPLESS CHANGE SPEED TRANSMISSION WITH ADJUSTABLE THROW CRANK MECHANISMFiled April 14, 1966 2 Sheets-Sheet 1 INVENTOR SHIGEO ISHIOKA law/MM imM ATTORNEYS Jan. 23, 1968 SHIGEO ISHIOKA SS CHANGE SPEED TRANSMISSIONWITH STEPLE ADJUSTABLE THROW CRANK MECHANISM Filed April 14, 1966 2Sheets-Sheet 2 SHIGEO ISHIOKA ATTORNEYS United States Patent ()fiice3,364,759 Patented Jan. 23, 1968 3,364,759 STEPLESS CHANGE SPEEDTRANSMISSION WITH ADJUSTABLE THROW CRANK MECHANISM Shigeo Ishioka, 3-3Yamate-dori, Showa-ku, Nagoya-ski, Japan Continuation-impart ofapplication Ser. No. 268,797, Mar. 28, 1963. This application Apr. 14,1966, Ser. No. 542,669 Claims priority, appiication Japan, Apr. 6, 1962,37/ 13,993 4 Claims. ct. 74-117 This application is acontinuation-in-part of my copending application Ser. No. 268,797, filedMar. 28, 1963, now abandoned.

The crank in a crank mechanism is the part of a mechanism fortransforming a rotational movement into a reciprocal linear movement orinto a reciprocal angular movement. If the length of the crank arm isvariable, the length of the stroke of the reciprocal linear movement orof the reciprocal angular movement in relation to one rotation of thecrank can be moved.

The present invention is directed to a crank mechanism in which thelength of the crank arm can be changed continuously while the crank isin rotation. The mechanism according to the present invention can beapplied to many types of apparatus, such as a stepless change gear, atorque converter, an apparatus for changing the stroke of the piston ofan internal combustion engine, and an apparatus for changing the strokeof the horizontal oscillating movement of electric fan.

The invention will be described hereinafter with reference toaccompanying drawings, in which:

FIG. 1 is a longitudinal cross sectional view of a stepless change gearincorporating the crank mechanism according to the present invention;

FIG. 2 is a horizontal cross sectional view on line 22 of FIG. 1;

FIG. 3 is a horizontal cross sectional view taken on line 33 of FIG. 1;

FIGS. 4 and 5 are diagrammatic end views showing the relationship amongthe crankshaft, inner crankshaft and crank pin of the apparatus of FIG.1;

FIG. 6 is a longitudinal cross sectional view of a modified form of theapparatus as shown in FIG. 1;

FIG. 7 is a sectional view of a modified form of the crankshaft portionof the apparatus of FIG. 1; and

FIG. 8 is a cross section taken on line 88 of FIG. 7.

FIG. 1 through FIG. 5 show a stepless change gear which includes anadjustable throw crank mechanism according to the present invention, andthe theory of the present invention will be described hereinafter basedon these figures. First, the construction and operation of the apparatusas shown in FIG. 1 will be described. A driving shaft 1 is adapted to beconnected to a suitable prime mover, and a driven shaft 2 is adapted tobe connected to a driven machine and is coaxial with the driving shaft.A plurality, in this case three, of crankshafts 3 are rotatably mountedin interior walls 5a of housing 5 and are disposed at equal distancesaround the axis of shafts 1 and 2. A corresponding plurality of rockingshafts 4 are also mounted in walls 5a and are disposed at equaldistances around the axis of shafts 1 and 2.

A sun gear 6 is fixed to driving shaft 1, and each crankshaft 3 has agear 7 fixed thereon which is in mesh with said sun gear 6. An innercrankshaft 8 is rotatably mounted within each crankshaft 3, the axis ofrotation of each said inner crankshaft being eccentric to that of thecrankshaft within which it is positioned. A crank pin 9 is afiixed toeach inner crankshaft 8. The relationship among the axis of rotation ofcrankshaft 3, the axis around which inner crankshaft 8 and the center ofcrank pin 9 rotates will be described later. A helical guide groove 10is provided on the outer circumferential surface of each innercrankshaft 8 and extends about 180 degrees (half the length of the pitchof said groove). An eccentric throwadjusting rod 11 is slidablypositioned in each crankshaft 3 and rotates with the crankshaft 3. Aprojection 12 is provided on each eccentric throw-adjusting rod 11 andis engaged in said guiding groove 10. Each inner crankshaft 8 willrotate in a clockwise or counter-clockwise direction an amount less than180 degrees within the crankshaft 3 when the eccentric throw-adjustingrods 11 are moved in one direction or the other along crankshaft 8. Theratio of the diameter of the inner crankshaft 8 and the pitch of thehelical guiding groove 10 must be determined by taking intoconsideration the maximum static friction coetficient and a value mustbe chosen which makes movement possible under no load conditions. Thisis to say, when the crank pin 9 is not under load, the eccentricthrow-adjusting rod 11 should move so as to rotate the inner crankshaft8 through an angular movement less than 180 degrees. However, when thecrank pin 9 is given a torque while the crankshaft 3 is fixed, the valueof the static friction coefiicient must be such that the eccentricthrow-adjusting rod 11 does not move in either direction along the innercrankshaft 8. An adjusting disc 13 is engaged with the ends of theeccentric throw-adjusting rods 11, said adjusting disc being engaged bya lever 14 which is disposed in the housing 5 so that the eccentricthrow-adjusting rods 11 are caused to move in the axial direction of thecrankshafts 3 when the lever 14 is moved. A rocking pin 15 is mounted onthe end of each rocking shaft 4, and each crank pin 9 is connected to acorresponding rocking pin by means of a link 16. The rocking shafts 4Will be reciprocated through less than a complete rotation with therotation of the crankshaft 3. The inner race of one way clutch device 17is aiiixed to the end of each rocking shaft 4 at the opposite end fromthe rocking pin 16, and a driven outer gear 18 is mounted on the outerrace of the one-way clutch device 17. A driven gear 19 which is in meshwith said driven outer gear 18 is mounted on said driven shaft 2.

The meshing of sun gear 6 and the three gears 7 is arranged so that thereciprocal movement of each rock ing shaft 4 is degrees out of phasewith each of the other two rocking shafts.

When the driving shaft 1 is rotated, the crankshafts 3 are caused torotate so as to oscillate the rocking shafts 4. However, the driven gear19 transmits torque to the driven shaft 2 by means of one-way clutchdevice 17 only when one of the rocking shafts is rotated in a certaindirection. The driven shaft 2 is nevertheless continuously supplied withtorque because the three rocking shafts are 120 out of phase with eachother. The present invention resides in the crankshaft 3 and the partsassociated therewith and the details thereof are described below.

FIGS. 4 and 5 show the relationship among the crankshaft 3, the innershaft 8 and crank pin 9. In the drawings, X designates the axis ofrotation of the crankshaft 3, and Y is the axis of rotation ofcrankshaft 8, and Z is the center of crank pin 9, the spacing of thepoints being such that XY=YZ.

Furthermore, the crankshaft 3, rocking shaft 4, crank pin 9, rocking pin15 and link 16 constitute a 4-part chain connection in the crankmechanism in which the distance X2 in the FIG. 4 is the length of thecrank arm, i.e. is the eccentric throw. To adjust eccentric throw byadjusting the length of the crank arm is the object of the presentinvention. FIG. 4 shows the condition Where the eccentricthrow-adjusting rod 11 has been moved to the left into crankshaft 3 asfar as it can go, and therefore the center Z of crank pin 9 is spaced asfar as possible from the axis of rotation X of the crankshaft 3. That isto say, the eccentric throw is the maximum value. Next, when theeccentric throw-adjusting rod 11 is moved to the right by means of thelever 14, the inner crankshaft 8 is rotated in the crankshaft 3 andsimultaneously the center Z of the crank pin approaches the axis ofrotation X of the crankshaft 3 while the rotation is continued. In otherwords, the eccentric throw is gradually decreased. When the eccentricthrow-adjusting rod 11 is shifted as far as it can go in the rightdirection, points X and Z coincide as shown in FIG. 5, and the eccentricthrow becomes zero. Accordingly, in the present apparatus, the eccentricthrow is adjusted by moving the lever 14, thereby to adjust the strokeof reciprocal rotational movement of the rocking shaft 4, and thereforethe present apparatus functions as a stepless change gear.

When the torque is applied to the inner crankshaft 8 due to a load beingdriven, the inner crankshaft will not rotate within the crankshaft 3even though an effort is made to move the lever 14 because the frictionbetween the guiding groove and projection 12 will be increased.According to the present apparatus, however, when torque is not appliedto the inner crankshafts 8 and not transmitted to the output shaftbecause of reciprocal angular movement of the rocking shafts 4 and theone-way clutch devices 17, the inner crankshaft can be rotated andadjustment of the eccentric throw can be effected. An adjusting spring2% is provided between each eccentric throw-adjusting rod 11 andadjusting disc 13 to smooth the production of tr e above adjustment.That is to say, when the lever 14 is operated, and the adjusting disc 13applies pressure on the eccentric throw-adjusting rods 11, and a torquedepending on the load is applied to one of the inner crankshafts 8accidentally, the corresponding adjusting spring 20 is compressed whenthe particular eccentric throwadjusting rod 11 is locked. However, whenthe direction of rotation of the corresponding rocking shaft 4 isreversed, no torque is applied to the corresponding inner crankshaft 8,and the eccentric throw-adjusting rod 11 starts to move under the actionof the compressed adjusting spring 211.

However, the adjusting spring 20 is not required due to the presence ofsuch factors as bending of the material of the eccentric throw-adjustingrods 11 and other such factors. Furthermore, where wear between theeccentric throw-adjusting rods 11 and adjusting disc 13 is a factor,thrust bearings or the like can be provided. Also, more than one guidegroove 19 can be provided in which case a corresponding number ofprojections 12 must be provided.

FIG. 6 illustrates an embodiment of the present invention asincorporated in a torque converter, the crankshafts which form part ofthe present invention are modified as compared with that shown inFIG. 1. In the apparatus according to FIG. 1, the eccentricthrow-adjusting rod 11 which causes the inner crankshaft 8 to rotatewithin each crankshaft 3 is positioned within the crankshaft 3, but inthe apparatus shown in FIG. 6, it is positioned on the outercircumference of each crankshaft and forms part of an eccentricthrow-adjusting ring 29.

In FIG. 6, similar to the embodiment shown in FIG. 1, an innercrankshaft 26 is loosely mounted in each crankshaft 25 so that it isfree to rotate relative to crankshaft 25 and at least one longitudinalgroove 27 is provided in each crankshaft 25. The width of saidlongitudinal groove is equal to the width of the projection 28 dependingfrom an eccentric throw-adjusting ring 29 loosely mounted around theouter circumference of each crankshaft 25. Ring 29 is movable in theaxial direction of the crankshafts 2-5, and the projection 28 is alsoengaged in a helical guiding groove 30 in the inner crankshaft 26.Guiding discs 31 are provided on the eccentric throw-adjusting ring 29,and an adjusting disc 32 is engaged between said guiding discs. A lever34 mounted on housing 33 is 4 coupled with said adjusting disc, and saidadjusting discs 32 and rings 29 are shifted by moving the lever to causethe eccentric throw-adjusting rings 29 to move in the axial direction ofthe crankshafts 25. By means of this arrangement and movement of thelever 34, the eccentric throw of the crank pins 35 is varied.

In the apparatus shown in FIG. 1, a driven outer gear 38 is afiixed tothe outer race of one-way clutch device 17, but in the apparatus shownin FIG. 6, a spring 38, shown in the drawing as a coil spring, isafiixed to the outer race 37 of each one-way clutch device 36, and theother end of said spring 38 is affixed to a driven outer gear 39.

Where a driven shaft 40 cannot be rotated because of an excessive loadapplied to the driven shaft, in the ap paratus shown in FIG. 1, thedriving shaft 1 is caused to stop, but in the apparatus shown in FIG. 6,repeated bending of the springs 38 occurs and the driving shaft 42 doesnot stop.

Accordingly, in the apparatus shown in FIG. 1, the position of the lever14 and the ratio of the speed of rotation of the driven shaft 2 to thatof the driving shaft 1 constitutes one dimensional relationship, but inthe apparatus shown in FIG. 6, the ratio of said speeds of rotation isvariable according to size of the load.

That is to say, the FIG. 1 device operates as a stepless change gearwhile the FIG. 6 device operates as a torque converter which will losespeed. The coupling of driven outer gears 39 and driven shaft 49 neednot be by external gear 43 as shown in the drawing, but can be throughan internal gear 44 which is shown in FIG. 6 in dotted lines. Therelationship of the sun gear on the drive shaft 42 and outer gears onthe crankshafts as shown in FIGS. 1 and 6 can be the same.

Also, in the apparatus of FIG. 1, as a means of reduc ing the unevenmotion of the torque of the driven shaft 2, conventional means can beprovided such as insertion of a buffer spring between the driven shaftgear 18 and the driven shaft 2 or provision of a flywheel of a suitabletype on the driven shaft.

FIG. 7 illustrates a modified crankshaft according to the presentinvention. In the apparatus, an eccentric throw-adjusting core 47 is thepart corresponding to the eccentric throw-adjusting rod 11 shown inFIG. 1. The adjusting disc 13 and lever 14 which actuate the eccentricthrow-adjusting rod 11 in the FIG. 1 in the direction of the axis ofcrankshaft 3 are replaced by hydraulic pressure which is suppliedthrough an oil groove 50 located in the housing 49. The eccentricthrow-adjusting core 47 has outwardly extending projections 47a engagingbetween 51a on the inner surface of a crankshaft 51. Core 47 also hasinwardly extending projections 47b engaging between threads 52a on theouter surface of an inner crankshaft 52. One of the threads 51a and 52ais a clockwise thread and the other is a counterclockwise thread.Alternatively one of the two threads can be parallel to the axis of theshafts, and can be lands defining longitudinal grooves.

The thread provided on the outer surface of said inner crankshaft 52corresponds to the guiding groove 10 in FIG. 1 and the thread providedin the inner surface of said eccentric throw-adjusting core 47corresponds to the projection 12 in FIG. 1. A restoring spring 53 isprovided between core 47 and the end of inner crankshaft 52 to provide abalance for the oil pressure. In order to cause the eccentricthrow-adjusting core 47 to move, mechanical means similar to those shownin FIG. 1 or FIG. 6 can also be used.

The features of the present invention are believed to be clear from thethree foregoing embodiments, but in summary thereof the eccentricthrow-adjusting rod 11 in FIG. 1, the eccentric throw-adjusting ring 29in FIG. 6 and the eccentric throw-adjusting core 47 in FIG. 7 areidentical with respect to their function, and these three devices can becalled the eccentric throw-adjusting members.

According to the present invention, the inner crankshaft is positionedWithin the crankshaft and is free to rotate within the crankshaft, andthe axis of rotation of the crankshaft is eccentric to the axis ofrotation of the inner crankshaft. The crank pin is mounted on the innercrankshaft, but the axis of rotation of the inner crankshaft iseccentric to the center of the crank pin.

The eccentric throw-adjusting member is movable along the crankshaftparallel to the axis of rotation. At least one guiding groove isprovided in the inner crankshaft, and a projection on the eccentricthrow-adjusting member engages in said guiding groove to cause theeccentric throw-adjusting member to rotate in inner crankshaft back andforth about 180 degrees when the eccentric throw-adjusting member ismoved in the axial direction of the crankshaft. The pitch of the guidinggroove is such that when a torque is applied between the crankshaft andthe inner crankshaft, the eccentric throw-adjusting member cannot shiftin the axial direction of the crankshaft. By means of the apparatusprovided in the housing, the eccentric throw-adjusting member can bemoved.

It is thought that the invention and its advantages will be understoodfrom the foregoing description and it is apparent that various changesmay be made in the form, construction and arrangement of the partswithout departing from the spirit and scope of the invention orsacrificing its material advantages, the forms hereinbefore describedand illustrated in the drawings being merely preferred embodimentsthereof.

1 claim:

1. A crank mechanism having a variable eccentric throw comprising acrankshaft, an inner crankshaft rotatably mounted in said crankshaftwith the axis of rotation of said crankshaft being parallel andeccentric to the axis of rotation of said inner crankshaft, a crank pinaffixed to said inner crankshaft, the center of rotation of said crankpin being eccentric to the axis of rotation of said inner crankshaft,and an elongated eccentric throw-adjusting member slidable within saidcrankshaft and parallel to the axis of said crankshaft, said innercrankshaft having at least one substantially helical guiding groovetherein, a projection on said throw-adjusting member engaged in saidguiding groove, said inner crankshaft being reciprocally rotatablethrough an angle of about 180 degrees within said crankshaft by themovement of said eccentric throw-adjusting member in the axial directionof said crankshaft, moving means operatively associated with saideccentric throw-adjusting member for moving it in the direction of theaxis of said crankshaft, and a resilient means between said moving meansand said throw-adjusting member.

2. A torque transmitting device comprising, a driving shaft, a drivenshaft coaxial therewith, at least one rocking shaft parallel to saiddriving and driven shafts, a variable eccentric throw comprising acrankshaft, an inner crankshaft rotatably mounted in said crankshaftwith the axis of rotation of said crankshaft being parallel andeccentric to the axis of rotation of said inner crankshaft, a crank pinafiixed to said inner crankshaft, the center of rotation of said crankpin being eccentric to the axis of rotation of said inner crankshaft,and an eccentric throw-adjusting member loosely mounted in operativerelationship with said crankshaft and movable in the direction ofrotation of and in a direction the same as the direction of the axis ofsaid crankshaft, said inner crankshaft having at least one guidinggroove therein, a projection on said throw-adjusting member engaged insaid guiding groove, said inner crankshaft being reciprocally rotatablethrough an angle of about degrees within said crankshaft by the movementof said eccentric throw-adjusting member in the axial direction of saidcrankshaft, moving means operatively associated with said eccentricthrow-adjusting member for moving it in the direction of the axis ofsaid crankshaft, a housing in which said driving shaft, said drivenshaft and said rocking shaft are rotatably mounted, said crankshaftbeing mounted in said housing parallel to said driving and driven shaft,a sun gear mounted on said driving shaft, a gear meshing with said sungear and mounted on said crankshaft, a rocking pin mounted on saidrocking shaft, a link connecting said rocking pin to said crank pin sothat said rocking shaft rocks when said crankshaft rotates, and one-wayclutch means coupling said rocking shaft to said driven shaft fortransmitting torque to said driven shaft only when said rocking shaft isrotating in one direction.

3. The combination as claimed in claim 2 in which said one-way clutchdevice is mounted on said rocking shaft and has an outer race, a drivenouter gear on the outer race of said one-way clutch device, and a drivengear meshing with said driven outer gear and mounted on said drivenshaft.

4, The combination as claimed in claim 2 in which said one-way clutchdevice is mounted on said rocking shaft, a driven gear mounted on saiddriven shaft, a driven outer gear meshing with said driven gear androtatably mounted on said rocking shaft, and at least one spring coupledbetween said one-Way clutch device and said driven outer gear.

References Cited UNITED STATES PATENTS 977,449 12/1910 Hayden 74-1171,304,955 5/1919 Fowler 74470 2,590,547 3/1952 Kolko 74-116 3,130,6034/1964 Gessner 74600 3,229,549 1/1966 Riedl 74-117 X MILTON KAUFMAN,Primary Examiner.

2. A TORQUE TRANSMITTING DEVICE COMPRISING, A DRIVING SHAFT, A DRIVENSHAFT COAXIAL THEREWITH, AT LEAST ONE ROCKING SHAFT PARALLEL TO SAIDDRIVING AND DRIVEN SHAFTS, A VARIABLE ECCENTRIC THROW COMPRISING ACRANKSHAFT, AN INNER CRANKSHAFT ROTATABLY MOUNTED IN SAID CRANKSHAFTWITH THE AXIS OF ROTATION OF SAID CRANKSHAFT BEING PARALLEL ANDECCENTRIC TO THE AXIS OF ROTATION OF SAID INNER CRANKSHAFT, A CRANK PINAFFIXED TO SAID INNER CRANKSHAFT, THE CENTER OF ROTATION OF SAID CRANKPIN BEING ECCENTRIC TO THE AXIS OF ROTATION OF SAID INNER CRANKSHAFT,AND AN ECCENTRIC THROW-ADJUSTING MEMBER LOOSELY MOUNTED IN OPERATIVERELATIONSHIP WITH SAID CRANKSHAFT AND MOVABLE IN THE DIRECTION OFROTATION OF AND IN A DIRECTION THE SAME AS THE DIRECTION OF THE AXIS OFSAID CRANKSHAFT, SAID INNER CRANKSHAFT HAVING AT LEAST ONE GUIDINGGROOVE THEREIN, A PROJECTION ON SAID THROW-ADJUSTING MEMBER ENGAGED INSAID GUIDING GROOVE, SAID INNER CRANKSHAFT BEING RECIPROCALLY ROTATABLETHROUGH AN ANGLE OF ABOUT 180 DEGREES WITHIN SAID CRANKSHAFT BY THEMOVEMENT OF SAID ECCENTRIC THROW-ADJUSTING MEMBER IN THE AXIAL DIRECTIONOF SAID CRANKSHAFT, MOVING MEANS OPERATIVELY ASSOCIATED WITH SAIDECCENTRIC THROW-ADJUSTING MEMBER FOR MOVING IT IN THE DIRECTION OF THEAXIS OF SAID CRANKSHAFT, A HOUSING IN WHICH SAID DRIVING SHAFT, SAIDDRIVEN SHAFT AND SAID ROCKING SHAFT ARE ROTATABLY MOUNTED, SAIDCRANKSHAFT BEING MOUNTED IN SAID HOUSING PARALLEL TO SAID DRIVING ANDDRIVEN SHAFT, A SUN GEAR MOUNTED ON SAID DRIVING SHAFT, A GEAR MESHINGWITH SAID SUN GEAR AND MOUNTED ON SAID CRANKSHAFT, A ROCKING PIN MOUNTEDON SAID ROCKING SHAFT, A LINK CONNECTING SAID ROCKING PIN TO SAID CRANKPIN SO THAT SAID ROCKING SHAFT ROCKS WHEN SAID CRANKSHAFT ROTATES, ANDON-WAY CLUTCH MEANS COUPLING SAID ROCKING SHAFT TO SAID DRIVEN SHAFT FORTRANSMITTING TORQUE TO SAID DRIVEN SHAFT ONLY WHEN SAID ROCKING SHAFT ISROTATING IN ONE DIRECTION.